Metamath Proof Explorer


Theorem dvgrat

Description: Ratio test for divergence of a complex infinite series. See e.g. remark "if ( abs( ( a( n + 1 ) ) / ( an ) ) ) >_ 1 for all large n..." in https://en.wikipedia.org/wiki/Ratio_test#The_test . (Contributed by Steve Rodriguez, 28-Feb-2020)

Ref Expression
Hypotheses dvgrat.z Z = M
dvgrat.w W = N
dvgrat.n φ N Z
dvgrat.f φ F V
dvgrat.c φ k Z F k
dvgrat.n0 φ k W F k 0
dvgrat.le φ k W F k F k + 1
Assertion dvgrat φ seq M + F dom

Proof

Step Hyp Ref Expression
1 dvgrat.z Z = M
2 dvgrat.w W = N
3 dvgrat.n φ N Z
4 dvgrat.f φ F V
5 dvgrat.c φ k Z F k
6 dvgrat.n0 φ k W F k 0
7 dvgrat.le φ k W F k F k + 1
8 3 1 eleqtrdi φ N M
9 eluzelz N M N
10 8 9 syl φ N
11 uzid N N N
12 11 2 eleqtrrdi N N W
13 10 12 syl φ N W
14 simpr φ k = N k = N
15 14 eleq1d φ k = N k W N W
16 14 fveq2d φ k = N F k = F N
17 16 fveq2d φ k = N F k = F N
18 17 breq2d φ k = N 0 < F k 0 < F N
19 15 18 imbi12d φ k = N k W 0 < F k N W 0 < F N
20 2 eleq2i k W k N
21 1 uztrn2 N Z k N k Z
22 20 21 sylan2b N Z k W k Z
23 3 22 sylan φ k W k Z
24 23 5 syldan φ k W F k
25 absgt0 F k F k 0 0 < F k
26 24 25 syl φ k W F k 0 0 < F k
27 6 26 mpbid φ k W 0 < F k
28 27 ex φ k W 0 < F k
29 3 19 28 vtocld φ N W 0 < F N
30 13 29 mpd φ 0 < F N
31 0red φ 0
32 14 eleq1d φ k = N k Z N Z
33 16 eleq1d φ k = N F k F N
34 32 33 imbi12d φ k = N k Z F k N Z F N
35 5 ex φ k Z F k
36 3 34 35 vtocld φ N Z F N
37 3 36 mpd φ F N
38 37 abscld φ F N
39 31 38 ltnled φ 0 < F N ¬ F N 0
40 30 39 mpbid φ ¬ F N 0
41 10 adantr φ F 0 N
42 38 adantr φ F 0 F N
43 simpr φ F 0 F 0
44 2 fvexi W V
45 44 mptex i W F i V
46 45 a1i φ F 0 i W F i V
47 24 adantlr φ F 0 k W F k
48 eqidd φ F 0 k W i W F i = i W F i
49 simpr φ F 0 k W i = k i = k
50 49 fveq2d φ F 0 k W i = k F i = F k
51 50 fveq2d φ F 0 k W i = k F i = F k
52 simpr φ F 0 k W k W
53 fvex F k V
54 53 a1i φ F 0 k W F k V
55 48 51 52 54 fvmptd φ F 0 k W i W F i k = F k
56 2 43 46 41 47 55 climabs φ F 0 i W F i 0
57 abs0 0 = 0
58 56 57 breqtrdi φ F 0 i W F i 0
59 47 abscld φ F 0 k W F k
60 55 59 eqeltrd φ F 0 k W i W F i k
61 2fveq3 i = N F i = F N
62 61 breq2d i = N F N F i F N F N
63 62 imbi2d i = N φ F N F i φ F N F N
64 2fveq3 i = k F i = F k
65 64 breq2d i = k F N F i F N F k
66 65 imbi2d i = k φ F N F i φ F N F k
67 2fveq3 i = k + 1 F i = F k + 1
68 67 breq2d i = k + 1 F N F i F N F k + 1
69 68 imbi2d i = k + 1 φ F N F i φ F N F k + 1
70 38 adantr φ N F N
71 70 leidd φ N F N F N
72 71 expcom N φ F N F N
73 38 ad2antrr φ k W F N F k F N
74 24 adantr φ k W F N F k F k
75 74 abscld φ k W F N F k F k
76 2 peano2uzs k W k + 1 W
77 ovex k + 1 V
78 eleq1 i = k + 1 i W k + 1 W
79 78 anbi2d i = k + 1 φ i W φ k + 1 W
80 fveq2 i = k + 1 F i = F k + 1
81 80 eleq1d i = k + 1 F i F k + 1
82 79 81 imbi12d i = k + 1 φ i W F i φ k + 1 W F k + 1
83 eleq1 k = i k W i W
84 83 anbi2d k = i φ k W φ i W
85 fveq2 k = i F k = F i
86 85 eleq1d k = i F k F i
87 84 86 imbi12d k = i φ k W F k φ i W F i
88 87 24 chvarvv φ i W F i
89 77 82 88 vtocl φ k + 1 W F k + 1
90 76 89 sylan2 φ k W F k + 1
91 90 adantr φ k W F N F k F k + 1
92 91 abscld φ k W F N F k F k + 1
93 simpr φ k W F N F k F N F k
94 7 adantr φ k W F N F k F k F k + 1
95 73 75 92 93 94 letrd φ k W F N F k F N F k + 1
96 95 ex φ k W F N F k F N F k + 1
97 20 96 sylan2br φ k N F N F k F N F k + 1
98 97 expcom k N φ F N F k F N F k + 1
99 98 a2d k N φ F N F k φ F N F k + 1
100 63 66 69 66 72 99 uzind4 k N φ F N F k
101 100 impcom φ k N F N F k
102 20 101 sylan2b φ k W F N F k
103 102 adantlr φ F 0 k W F N F k
104 103 55 breqtrrd φ F 0 k W F N i W F i k
105 2 41 42 58 60 104 climlec2 φ F 0 F N 0
106 40 105 mtand φ ¬ F 0
107 eluzel2 N M M
108 8 107 syl φ M
109 108 adantr φ seq M + F dom M
110 4 adantr φ seq M + F dom F V
111 simpr φ seq M + F dom seq M + F dom
112 5 adantlr φ seq M + F dom k Z F k
113 1 109 110 111 112 serf0 φ seq M + F dom F 0
114 106 113 mtand φ ¬ seq M + F dom
115 df-nel seq M + F dom ¬ seq M + F dom
116 114 115 sylibr φ seq M + F dom